Akademik Veri Yönetim Sistemi
IV. International Turkic World Congress on Science and Engineering 23-24 June 2022, Niğde - Türkiye, Niğde, Türkiye, 23 - 24 Haziran 2022, ss.863-868, (Tam Metin Bildiri)
Seawater open-cycle cooling water systems are widely used in facilities where cooling water is needed, such as shoreline located thermal power plants. Since extreme temperature changes can occur in the discharge area where the cooling water returns to the sea, the ecological balance can be maintained by diluting the thermal wastewater by using submerged marine outfalls. Especially in cases where the thermal wastewater flow rate is low, thermal wastewater marine outfalls with a horizontally located circular single-port diffuser can be used. Thermal wastewater discharged horizontally to the marine environment creates forms a positively buoyant jet in the stagnant and unstratified receiving water. In the literature, there are studies showing that impact point dilution of relatively small sized horizontal single-port diffuser having thermal outfalls can be increased when a downward inclination angle applied on the nozzle. In this study, it is hypothetically investigated to increase the impact point dilution performance by applying a downward inclination angle of the thermal wastewater marine outfall, which has a horizontally located single circular port diffuser with a diameter of 0.4 m, which is slightly larger than the one in the literature. In the study, it was calculated with the UM3 model of the Visual Plumes program developed by the US Environmental Protection Agency. Within the scope of the study, the initial temperature difference is +10°C, the receiving water density is 1025 kg/m3, the densimetric Froude number is 20 and the discharge depths are 10m, 20m, 30m, 40m and 50m. Impact point dilutions and riser heights were calculated in the horizontal and downward inclination states of the discharge nozzle under modified conditions. As a result of the study, the average optimum downward inclination angle and the maximum impact point dilution rate of increase were found to be approximately 15° and 2.5%, respectively. It has been found that the maximum impact point dilution rate of increase is approximately 5% and can be achieved at a downward inclination angle of approximately 19° for a discharge depth of 10m.
Key Words: Downward inclination jet, Marine outfall, Positively buoyant jet, Thermal wastewater discharge, Visual Plumes